The present invention is a method for the redistribution of trichlorosilane in the presence of N,N,N',N'-tetraethylethylenediamine (TEEDA) to form a complex comprising dichlorosilane and TEEDA. The dichlorosilane can be disassociated from the TEEDA by a means such as heating and then used in standard processes requiring dichlorosilane. Alternatively, the complex comprising the dichlorosilane and TEEDA can be used as a reactant for hydrosilation of .alpha.,.beta.-unsaturated olefinic nitriles or reacted with Grignard type reagents to make organosilanes.
Typical processes for producing chlorosilanes, such as the reaction of hydrogen chloride with particulate silicon, result in a product that is primarily trichlorosilane. The ability to redistribute trichlorosilane to dichlorosilane can provide flexibility in meeting the demand for each of these chlorosilanes. Under typical uncatalyzed conditions the redistribution of trichlorosilane results in only about a 15 mole percent redistribution of trichlorosilane to dichlorosilane. The present method can provide for essentially a 100 mole percent redistribution of trichlorosilane to dichlorosilane. Therefore, the present method provides a more efficient method for redistribution of trichlorosilane to dichlorosilane. Furthermore, the present method provides a complex comprising dichlorosilane and TEEDA that is a solid and can be more easily and safely handled than dichlorosilane, which, under ambient conditions is a gas.
It is known that certain nitrogen containing compounds can catalyze the redistribution of chorohydrogen silanes. For example, Jex et al., U.S. Pat. No. 3,044,845, teach that dichlorosilane can be produced from trichlorosilane by forming a mixture of trichlorosilane, hexamethyltriaminotriazine or pyridine or a hydrocarbon-substituted pyridine as a catalyst and, as a promoter for the catalyst, a liquid halohydrocarbon in which trichlorosilane is soluble and heating the mixture.
Marin, U.S. Pat. No. 4,038,371, teaches that trichlorosilane is redistributed to dichlorosilane in the presence of a tetraalkylurea as a catalyst.
Lepage et al., U.S. Pat. No. 4,746,752, teach that silanes can be redistributed in the presence of a catalyst comprising (i) a quaternary ammonium salt or quaternary phosphonium salt, (ii) a tertiary amine, or (iii) an ion-exchange resin comprising tertiary amine or quaternary ammonium groups.
Matthes et al., U.S. Pat. No. 5,026,533, teach that an alkylamino trialkoxysilane chemically bound on a support is catalytic for the redistribution of trichlorosilane to dichlorosilane.
The cited art does not recognize that N,N,N',N'-tetraethylethylenediamine (TEEDA) can redistribute trichlorosilane to form a complex comprising dichlorosilane and the TEEDA.